06-26-2017 01:53 AM - edited 03-08-2019 11:06 AM
What is Native Vlans and what is the requirement of Native Vlans?
please explain with example
06-26-2017 04:36 AM
Hi Muraripadhan,
It's quite basic networking level question but my assumption it's that you know the basic networking stuff (you know what VLAN is, etc.) and you're just confused.
Native vlan (by default vlan 1 & it's recommended to change that vlan to a different ID) it the vlan which is untagged.
Native vlan is used on the network for few different purposes. For example protocols such as VTP, STP or CDP are using native vlan to exchange specific information. To keep you network free from native vlan errors it's recommended to keep native vlan matched across your network.
Another purpose of native vlan usage it's the management connection to your switch/router. What you're doing here to allow this type of connection it's you're assigning IP address to your native vlan and then you're presenting it on the switch/router interface.
For example your laptop sits on 192.168.1.2 255.255.255.0 and you want SSH to your SW1.
1. First via console cable you're assigning IP address to your VLAN 1 by:
interface vlan 1
ip address 192.168.1.3 255.255.255.0
no shut (just in case)
2. Make sure that interface to which laptop is connected is in access mode and is open:
interface Gi1/0
switchport mode access
switchport access vlan 1 (don't need this because this is a default for vlan 1)
no shut
3. By this point you should be able to ping your SW1 from your laptop. SSH will start working once is configured on the switch.
You can stretch this connection via native/untagged vlan via trunk link too and go via multiple switches, Just do below:
1. Assign an IP address on the same subnet to each switch (192.168.1.2,3,4,5,etc)
2. Configure interface as trunk by following below:
interface XXX
switchport mode trunk
switchport trunk allowed vlan add XXX (any tagged vlans)
switchport trunk native vlan 1
3. Make sure that trunk interface XXX is open
interface XXX
no shut
All above config examples are just basic but hopefully they will be helpful for you.
If you need more help just let me know.
Thanks!
06-26-2017 04:55 AM
thank you dear
Ya i know but little bit confused about native vlan .Thank you dear
06-26-2017 06:15 AM
The native VLAN is to define what VLAN untagged frames belong to.
Used with tagged frame ports, frames sent out from the native VLAN are untagged. Frames received on such a port, without a VLAN tag are assumed to belong to the native VLAN.
The requirement for native VLAN is to define what's the native VLAN if you don't want to use the default on a trunk port (which is VLAN 1, by default, on trunk ports).
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